python - 使用 solvePnPRansac() - 姿势估计“解包的值太多”

Question

我正在尝试运行本教程中的代码 - Pose Estimation ,

调用 solvePnPRansac 函数后，出现以下错误:

rvecs, tvecs, inliers = cv2.solvePnPRansac(objp, corners2, mtx, dist)

ValueError: too many values to unpack

根据文档:

Python: cv2.solvePnPRansac(objectPoints, imagePoints, cameraMatrix, distCoeffs[, rvec[, tvec[, useExtrinsicGuess[, iterationsCount[, reprojectionError[, minInliersCount[, inliers[, flags]]]]]]]]) → rvec, tvec, inliers

有人处理过这个问题吗？

(Python 2.7，OpenCV 3b)

Answer 1

异常表示返回的值超过 3 个。 OpenCV3 已经改变了很多方法签名，不幸的是没有真正记录它。我检查了 solvepnp.cpp，签名如下:

bool cv::solvePnPRansac(InputArray _opoints, InputArray _ipoints,
                    InputArray _cameraMatrix, InputArray _distCoeffs,
                    OutputArray _rvec, OutputArray _tvec, bool useExtrinsicGuess,
                    int iterationsCount, float reprojectionError, double confidence,
                    OutputArray _inliers, int flags)

这似乎表明什么都没有改变。然而，在 python 中:

solvePnPRansac(...)
solvePnPRansac(objectPoints, imagePoints, cameraMatrix, distCoeffs[, rvec[, tvec[, useExtrinsicGuess[, iterationsCount[, reprojectionError[, confidence[, inliers[, flags]]]]]]]]) 
-> retval, rvec, tvec, inliers

所以尝试一下可能会有所帮助:

_, rvecs, tvecs, inliers  = cv2.solvePnPRansac(objp, corners2, mtx, dist)

或者如果您只想解压最后 3 个元素:

rvecs, tvecs, inliers  = cv2.solvePnPRansac(objp, corners2, mtx, dist)[:-3]